Germanium dual-fin field effect transistor
View Patent ↗In one example, a field effect transistor includes a pair of fins positioned in a spaced apart relation. Each of the fins includes germanium. Source and drain regions are formed on opposite ends of the pair of fins and include silicon. A gate is wrapped around the pair of fins, between the source and drain regions.
1. A method for fabricating a field effect transistor, the method comprising:
providing a pair of fins positioned in a spaced apart relation, each of the fins in the pair of fins formed from a first material comprising germanium;
providing source and drain regions formed on opposite ends of the pair of fins, wherein the source and drain regions are formed from a second material, different from the first material, comprising silicon; and
providing a gate wrapped around the pair of fins, between the source and drain regions.
2. The method of claim 1 , wherein the source and drain regions are formed of doped silicon.
3. The method of claim 2 , further comprising:
providing an extension positioned beneath the source and drain regions, wherein the extension is formed of doped silicon.
4. The method of claim 3 , wherein the extension is N+ doped, and the doped silicon of the source and drain regions is N++ doped.
5. The method of claim 4 , wherein a doping concentration of the extension is between approximately 5e18 and 5e19 electrons per cubic centimeter, and a doping concentration of the source and drain regions is above approximately 1e20 electrons per cubic centimeter.
6. The method of claim 3 , wherein the extension is P+ doped, and the doped silicon of the source and drain regions is P++ doped.
7. The method of claim 1 , wherein the field effect transistor is an N-type field effect transistor.
8. The method of claim 1 , wherein the germanium is epitaxially grown over silicon.
9. A method for fabricating a field effect transistor, the method comprising:
providing a pair of fins positioned in a spaced apart relation, each of the fins in the pair of fins formed from a first semiconductor material;
providing source and drain regions formed on opposite ends of the pair of fins, wherein the source and drain regions are formed from a second semiconductor material different from the first semiconductor material; and
providing a gate wrapped around the pair of fins, between the source and drain regions.
10. The method of claim 9 , wherein the first semiconductor material is germanium.
11. The method of claim 10 , wherein the germanium is epitaxially grown over the second semiconductor material.